Re: Hyperfocal focusing: Use judgment first!

[P3D Eric Goldstein <egoldste@xxxxxx>]

Dr. George A. Themelis wrote:

> The book that I just read, convinced me about the potential misapplications
> of the hyperfocal focusing.  I now believe that the photographer should use
> judgment above the hyperfocal practice.  The question is, which is the main
> object being photographed and what is the finest detail required to be
> captured on film?  This question should always be kept in mind when doing
> critical (in terms of sharpness/ resolution) work.

Depth of field and image sharpness is a fascinating area and one which
is more complex that most people realize, even seasoned photographers.
Each lens design creates a sharpness cone of different dimension and
shape, and so different lens designs of the same focal length actually
produce different depths of field! An extreme example of this are some
of the turn of the century designs (including some of the Rapid
Rectalinears) which instead of a sharp image cone with a sharp point of
focus was more characterized by an image cylinder which while never
needle sharp had a tremendous range of acceptable sharpness or DOF.

Without getting too pedantic about it, Dr. T's statement about focus is
true for every aspect of photography, stereo, plano, b/w, color; namely
that we can start with simple procedures to help us get a useable image
in many/most situations, but this only takes us so far. We can rely on
the DOF tables as a starting point or for snap shot or grab situations,
and in fact many famous photojournalists would prefocus or zone focus to
get their shots, which is roughly the same idea, and the results are
some of the most celebrated photos of our time. But selective focus is a
mainstay of the creative photographer's "weapons," and preset DOF from 5
ft -> inf isn't often making best use of it.

And yes, there are those of us who don't subscribe to the belief that
everything in the superior stereo shot must be in sharp focus, and that
selective focus is a tool for the stereographer as well as the plano
photographer.

Flame suit on... Eric G.


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